1. Field of the Invention
This invention relates generally to devices for delivering a fine mist spray to cool an area by evaporative cooling, and more particularly concerns a fan propelled misting apparatus for providing a high velocity flow of air and a finely divided mist for evaporative cooling of wide areas.
2. Description of Related Art
While heated vaporizers provide humidifying vapors, atomizer type humidifiers typically generate a cooling mist. Such devices for providing a cooling mist are useful for efficiently and economically cooling large areas such as sections of outdoor amusement parks, and smaller areas such as a garden area, or even a single person. A portable misting device utilizing a pressurizable fluid tank and an atomizing nozzle for providing a finely divided water vapor mist is disclosed in U.S. Pat. No. 5,775,590, which is incorporated by reference herein.
Another type of conventional portable spray device provides a water spray, body massager, and a fan. Various types of cool mist humidifiers are also known that have a fan for distributing a mist. One high capacity device has a water driven fan that provides a water misted source of cool air for fighting fires. Another typical type of portable misting device includes a hand held spray applicator such as a spray bottle, and a low speed fan, so that the device typically needs to be placed within a distance of four inches or less from the user, in order to achieve any significant cooling effect for the user.
It would be desirable to provide a cooling device that not only provides an evaporative cooling effect from the evaporation of a water mist, but also takes advantage of the wind chill effect that occurs when wind blows across a person""s bare skin, and thereby removes heat. The wind chill effect is typically quantified as a wind chill equivalent air temperature that at a standard wind speed would produce the same heat loss as the given temperature and wind speed, as a measure of the cooling power of a given wind speed on a person""s bare skin, at a given temperature. For example, a 35xc2x0 F. temperature wind speed of 5 MPH results in a wind chill equivalent air temperature of 33xc2x0 F.; a 35xc2x0 F. temperature wind speed of 10 MPH results in a wind chill equivalent air temperature of 22xc2x0 F.; and a 35xc2x0 F. temperature wind speed of 15 MPH results in a wind chill equivalent air temperature of 16xc2x0 F.
In order to increase the evaporative cooling effect of a water vapor mist, and to increase the wind chill effect, it would thus be desirable to provide a high speed air flow such as can be provided by a high speed fan. Small portable hand-held fans operating at about 6,000 RPM are known that can achieve a significant wind velocity at a close range such as about four inches or less, but such fans typically include blades that are low pitched and soft, and do not displace a sufficient amount of air to achieve a significant wind velocity at greater distances. In addition, the fanned air from such hand held fans readily disperses at a more convenient distance of about 18 inches from the fan, so that for delivery of such a cooling mist over distances of about 18 inches or greater, it would also be desirable to provide a generally laminar air flow for carrying and evaporating the mist, to allow such a laminar flow of air to resist dispersal while still efficiently mixing with a water vapor mist, achieving an effective wind chill factor to provide a more effective evaporative cooling from the water vapor mist before it is dispersed, and to reduce the power requirements and high velocities necessary to achieve a prolonged period of air flow about the water vapor mist. The present invention meets these needs.
Briefly, and in general terms, in one currently preferred embodiment, the present invention provides for an improved water vapor misting apparatus for generating a cooling water vapor mist, and generating a contained laminar, high speed air flow carrying the water vapor mist to increase the evaporative cooling effect of the water vapor mist, allowing the cool water vapor mist to be directed more effectively over greater distances. A water atomizer dispenses a water vapormist within a hollow discharge tube which provides a guidant path for air directed from a fan or impeller. The fan propelled misting apparatus can advantageously propel the finely divided mist toward the user, or a crowd, for example, and can be used to propel the mist for a number of feet by hand directing the discharge tube.
Thus in the first embodiment, the invention accordingly provides for a fan propelled misting apparatus for cooling an extended area by evaporative cooling, comprising a misting device and a blower. The blower advantageously includes a hollow, cylindrical mist discharge tube, and a high speed fan for propelling air flow through the mist discharge tube. The misting device is connected to the blower for delivering a fine spray of fluid to a distal portion of the cylindrical mist discharge tube, where the mist effectively mixes with a laminar air flow provided by the fan to increase the evaporative cooling effect of the water vapor mist.
In a presently preferred aspect of the first embodiment of the invention, the misting device comprises a pressurizable fluid tank with a water supply tube connected between the pressurizable fluid tank and the mist discharge tube for delivering the fine spray of water to the cylindrical mist discharge tube. The water supply tube preferably has a nozzle at a distal end of the water supply tube disposed in the mist discharge tube so as to deliver the fine spray of water in the air flow provided by the blower. The misting device also preferably further comprises a valve for controlling flow of water through the water supply tube. In one presently preferred embodiment, the pressurizable fluid tank comprises a piston type pump having a handle, and a removable cap allowing for filling of the pump with water. In another presently preferred aspect, the blower comprises a propeller, a motor driving the propeller, and a switch controlling operation of the motor. In the first preferred embodiment, the pressurizable fluid tank is disposed externally; and in a second preferred embodiment, the pressurizable fluid tank is disposed internally, such as in the handle;
In a third presently preferred embodiment, the fan propelled misting apparatus comprises a waist pack adapted to be secured to a user""s waist, with a fan disposed in the waist pack. The fan has a housing with an intake opening, and an exhaust opening directed toward the user""s face when the waist pack is secured to the user""s waist. A misting device is also provided in the waist pack for delivering a fine spray of water adjacent to the fan exhaust opening. In one presently preferred aspect, the misting device comprises a spray bottle having a water tank and a cap, with an intake tube and a spray pump having a nozzle directable adjacent to said exhaust opening of said fan. In other presently preferred aspects, the waist pack typically includes a waist strap for securing the waist pack to the user""s waist, and the waist pack includes a battery power supply for the fan. In another presently preferred aspect, the fan housing is bell shaped, with the cross-sectional area of the intake opening being larger than the cross-sectional area of the exhaust opening, and the fan preferably employs a high speed motor having a rotational speed of up to 10,200 RPM, that is capable of providing an air velocity of about 17 mph approximately 18 inches from the exhaust opening of the fan.
These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.